Übung 3 - Aufgabe 1

aufgabe03/Makefile

+# This makefile compiles all C files in the same directory and produces a single
+# executable named solution
+CC = gcc
+CFLAGS = -std=c11 -Wall -Wextra -pedantic -O2 -g -pthread  # this uses the C11 standard, if you want to use a different standard, change it to -std=c[NUMBER]
+CPPFLAGS = -MMD
+LD_FLAGS = -lm
+
+BIN_NAME = solution
+SRC_FILES = $(wildcard *.c)
+OBJ_FILES = $(SRC_FILES:.c=.o) 
+DEP_FILES = $(wildcard *.d)
+
+run: $(BIN_NAME)
+	./$(BIN_NAME)
+
+include $(DEP_FILES)
+
+$(BIN_NAME): $(OBJ_FILES)
+	$(CC) $(CPPFLAGS) $(LD_FLAGS) $(OBJ_FILES) -o $@
+
+%.o: %.c
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@ 
+
+clean:	
+	@rm -v *.o *.d
+	@rm -v ./$(BIN_NAME)
+
+.PHONY: run clean

aufgabe03/aufgabe1.c

+// simple example for pthreads
+#include <pthread.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include<unistd.h>
+
+#define NUM_THREADS     4
+#define NUM_SIM         10000
+
+int kollisionen;
+long thread_start[NUM_THREADS];
+long thread_end[NUM_THREADS];
+pthread_mutex_t lock;
+
+int level[NUM_THREADS];
+int last[NUM_THREADS];
+// int favoured;
+
+void *driveAuto(void *threadid)
+{
+  long tid;
+  tid = (long)threadid;
+  int _error = 0;
+  struct timeval tv;
+  
+  //Beginn kritischer Abschnitt
+  _error = pthread_mutex_lock(&lock);
+  
+  gettimeofday(&tv,NULL); //Zeitpunkt, wann das Auto losfaehrt.
+  thread_start[tid]=tv.tv_usec; //Speichert Startzeitpunkt von Auto pid
+
+  // printf("Hehe Car %ld is driving\n", tid);
+  sleep(0.001); //Auto faehrt ueber Bruecke
+
+  gettimeofday(&tv,NULL); //Zeitpunkt, wann das Auto ankommt.
+  thread_end[tid]=tv.tv_usec; //Speichert Endzeitpunkt von Auto pid
+
+  _error = pthread_mutex_unlock(&lock);
+  //Ende kritischer Abschnitt
+  
+  pthread_exit (NULL);
+}
+
+int main (void)
+{
+  pthread_t threads[NUM_THREADS];
+  int rc;
+  long t;
+  
+  //inital data
+  for (int i = 0; i < NUM_THREADS; i++) {
+    level[i] = 0;
+    last[i] = 0;
+  }
+  kollisionen = 0;
+  
+  // init lock
+  pthread_mutex_init(&lock, NULL);
+
+  for(int i= 0;i<NUM_SIM;i++){ //Anzahl der Simulationen
+    for(t=0; t < NUM_THREADS; t++) {
+      // printf ("In main: creating thread %ld\n", t);
+      rc = pthread_create (&threads[t], NULL, driveAuto, (void *)t);
+      if (rc) {
+        printf ("ERROR; return code from pthread_create () is %d\n", rc);
+        exit (-1);
+      }
+    }
+  
+    // joining threads
+    for (t = 0; t < NUM_THREADS; t++) {
+      pthread_join (threads[t], NULL);
+    }
+
+    //berechne, ob Autos kollidiert sind
+    
+    for(int k=0;k<NUM_THREADS;k++){
+      for (int l=0;l<NUM_THREADS;l++) {
+        if ((thread_start[k] < thread_end[l] && thread_start[k] > thread_start[l]) ) {
+          kollisionen++;
+        }
+      }
+    }
+    
+
+
+  }
+
+
+  printf("Simulationen: %d\n",NUM_SIM);
+  printf("Kollisionen: %d\n",kollisionen);
+    // for(int i=0;i<NUM_THREADS;i++){
+    //   printf("%ld , %ld\n", thread_start[i], thread_end[i]);
+    // }
+    //
+  /* Last thing that main() should do */
+  pthread_exit(NULL);
+}

aufgabe03/aufgabe1.d

+aufgabe1.o: aufgabe1.c